This invention relates to automotive door check devices, and in particular to a compact mechanical device capable of holding an automotive door in a number of predetermined open positions with a predetermined force.
It has been found useful to check the movement of an automotive door in a number of predetermined open positions to assure convenient and safe ingress/egress of the occupants. The door is normally checked against movement in at least one open position with an effort or resistive force adequate to resist wind gusts and the effect of parking on a grade.
The most common form of automotive door check is a mechanical device that resists motion by releasably storing energy in response to forced motion of the system. These devices, located between the vehicle pillar and door, can be configured to be integral with the door hinge or separate as autonomous mechanical assemblies. Energy storage is generally achieved by using a form of spring with coil and torsion arrangements being the most popular configurations. As the door is opened or closed, the door check device is configured to release energy entering the check positions and to store it when moving out of the check positions. The most common method of storing energy in the spring system is by means of a cam arrangement that moves in conjunction with the door. This cam can work within the hinge to ultimately produce a torque around the pivot axis of the hinge, or can work linearly in a separate checking device which produces a force vector to resist door movement at selected open positions.
Because the door check device must be located between the vehicle pillar and door, it is forced to occupy a severely restricted package space; there is limited clearance between the vehicle pillar and the door. Additionally, the weight of the door check device must not be too great; a significant proportion of the door check system mass resides within the door profile; the door swings on a pivot and is highly sensitive to weight. The size and weight of this device are therefore critical design parameters. The main focus of a door check development is to attain the required check efforts in the smallest possible package at the lowest achievable weight. The type of spring and its related strain energy storage capability combined with the package efficiency of the actuation mechanism dictate the overall effectiveness of the door check system.
The present invention is targeted at reducing the weight, cost, complexity and packaging space of an automotive door system checking device. It specifically packages the check effort generating component inside the hinge assembly, coaxial with the hinge pivot axis using a highly space efficient energy storage means. The hinge assembly normally comprises a hinge door component, a hinge body component, and a pivot pin linking these components and allowing them to rotate relative to each other about the pivot pin axis.
Accordingly, in a major aspect, the door checking apparatus for an automobile comprises:
(a) an array of needle bearings held in contact with a bearing surface comprising axially oriented grooves, by means of a resilient energy storage device;
(b) a cylindrical cage coaxially disposed adjacent to the bearing surface and comprising an axially oriented array of slots arranged to retain the needle bearings;
(c) means to impart rotary motion to the cylindrical cage to cause the needle bearings to move relative to the bearing surface to create a torque reaction in response to deflection of the resilient energy storage device as the needle bearings move into and out of the grooves;
(d) means to transmit the imparted torque from the bearing surface into an appropriate structure;
such that when the door checking apparatus is mounted between an automobile door and an automobile body, the rotary movement of the door is checked with predetermined force at positions determined by the relationship between the needle bearings and the grooves.
In further aspects of the invention, the bearing surface comprises the outer surface of a cylindrical shaft or, alternatively, the inside cylindrical bore of a housing member. In a further aspect of the invention, the resilient energy storage device is a coil spring disposed so that energy is stored in response to radial expansion caused by the motion of needle bearings into and out of shaft grooves.
In a further aspect of the invention, the resilient energy storage device is a coil spring disposed so that energy is stored in response to radial compression caused by the motion of the needle bearings into and out of the grooves.
In further aspects of the invention, the profiles of the grooves in the outer surface of the cylindrical shaft, or alternatively, inside the cylindrical bore, are shaped so that the summation of the torque reactions of the needle bearings results in the total required door system check effort.
In a further aspect of the invention, the grooves are arranged circumferentially on the shaft so as to correspond with the door system""s check position angles.
In a further aspect of the invention, the grooves are arranged circumferentially inside the cylindrical bore of the housing member so as to correspond with the door system""s check position angles.
In a further aspect of the invention, a grooved shaft and cylindrical cage are coaxially disposed with the pivot pin of an automobile door hinge and rotary motion is imparted by the hinge door component and the developed torque is transmitted out of the grooved shaft by the hinge body component.
In a further aspect of the invention, the housing member and cylindrical cage are coaxially disposed with the pivot axis of an automobile door hinge and rotary motion is imparted by the hinge door component via the housing member and the developed torque is transmitted out of the cylindrical cage by the hinge body component.